Surface and pit furnace safety maintenance cage



Oct. 13, 1959 J. H. REIGHART SURFACE AND PIT FURNACE SAFETY MAINTENANCECAGE Filed Oct. 21, 1957 2 Sheets-Sheet 1 Q N WIDHQZ A a INVEN'TOR.Jzmelikebglzarl SURFACE AND PIT FURNACE SAFETY MAINTENANCE CAGE FiledOct. 21, 1957 Oct. 13, 1959 J. H. REIGHART 2 Sheets-Sheet 2 IN V E NTOR. JazzeflRezylzwr BY 9 & r

ATTORAEYS United States Patent Ofiice SURFACE AND PIT FURNACE SAFETYMAINTENANCE CAGE June H. Reighart, Cleveland, Ohio, assignor to StickerIndustrial Supply Corporation, Cleveland, Ohio, a corporation of OhioApplication October 21, 1957, Serial No. 691,449 6 Claims, (Cl. 189-1)The invention relates to a cage adapted to be temporarily placedwithin atop-opening surface or pit furnace, such as heating and meltingfurnaces, soaking pits and the like, for the purpose of permittingworkmen to enter the furnace or pit for making repairs, immediatelyafter the charge has been removed and the fuel has been shut oif, withcomplete safety and comfort for the workmen.

Due to the extreme temperatures under which such of from 8' to 16 hoursafter a charge is removed from a furnace and the fuel shut 01f, beforeit is possible for workmen to enter the furnace for the purpose ofinspection and repairs.

This cooling-off period adds considerably to the shutdown time duringwhich a furnace is out of production, thus adding to the production costof the entire mill or plant. In cases where two furnaces are providedwith a common dividing wall, it is frequently necessary to shut downboth of the furnaces in order to accomplish the maintenance of eitherone or the other, thus further adding to the cost of production. i

The presentinvention contemplates the provision of a safety maintenancecage by means of which workmen may enter 'a top-opening furnace orsoaking pit immediately after a charge has been removed from the furnaceand fuel shut off, and may work with complete safety and comfort to makeany necessary repairs to the furnace or pit in order to again place itin proper condition for use.

It is therefore a primary object of the invention to provide atop-opening furnace or pit maintenance safety cage for overcoming theabove-mentioned disadvantages and difiiculties of present practice.

Another object is to provide such a cage which may be lowered into atop-opening furnace or pit as soon as the .charge has beenremovedtherefrom and the fuel turned off, and into which workmen mayimmediately enterto inspect and repairdamaged areas of the walls, floor,coping, burner ports, burners, etc.

A further object is to provide a furnace maintenance cage of thecharacter referred to which will protect the workmen from the intenseheat of the furnace or pit, and in which a downdraft will be induced tocontribute to the .comfort and safety of the workmen.

A still further object is to provide a maintenance cage of this typecomprising an open-top steel shell of a size n and shape to be receivedwithin the furnace or pit, the side walls and bottom thereof being linedwith suitable refractory or other heat insulation material.

It is also an object of the invention to provide a maintenance cage inwhich the floor is madeof slidable sections, whereby access may be hadto any desired portion of the floor of the furnace or pit for makingrepairs or replacements thereto.

Furthermore, it is an object of the invention to provide a cage of thischaracter having inwardly opening doors at various heights and invarious locations upon the side walls of the cage.

Another object of the invention is to providesuch a maintenance cagehaving permanent openings atthe bottom corners of opposite walls toinsure a constant downdraft through the cage. t

A further object of the invention is to provide a cage of the typereferred to having feet or legs at the comers thereof so as to supportthe cage with the bottom thereof spaced above the bottom of the furnaceor pit in which it is placed.

Still another object of the invention is to provide a maintenance cageof the character referred to having an approach platform at its openupper end, a ladder attached to a side wall of the cage adjacent to theapproach platform, and internal platforms at various heights, so thatworkmen within the cage will have access to high points on the walls andcoping of the furnace or pit in which the cage is located.

The above and other objects, apparent from the drawings and followingdescription, may be attained, the above described difliculties overcomeand the advantages and results obtained, by the apparatus, construction,arrangement and combinations, subcombinations and parts which comprisethe present invention, a preferred embodiment of which, illustrative ofthe best mode in which applicant has contemplated applying theprinciple, being set forth in detail in the following description andillustrated in the accompanying drawings.

The invention may be briefly described in general terms as comprising atop-opening furnace or pit maintenance safety cage in the form of asteel shell of a size and shape to be received within a furnace or pit,with feet or legs at the corners of the shell for supporting it spacedabove the bottom of the furnace or pit, a refractory lining within thebottom and side walls of the shell and a cranehandling bail at the opentop of the cage, whereby it may be positioned within or removed from anopen-top furnace or pit.

Permanent openings are provided in the lower portions of the side wallsat opposite corners of the cage, in order to induce a constantdown-draft through the cage. An approach platform is connected to thetop of the cage with hand rails thereon, and a ladder is attached to anadjacent side Wall of the cage so that a workman may descend from theapproach platform into the cage.

Internal platforms are provided at different heights within the cage,and inwardly opening doors are provided at different heights anddiiferent locations in the side walls of the cage, so that a workmanstanding upon one or another of these platforms may have access to thecoping, burners or burner ports or other areas at various heights on theside walls of the furnace or pit.

The. bottom of the cage is formed of a plurality of horizontallyslidable sections each comprising a steel shell with refractory liningtherein, whereby access may be had through the bottom of the cage toevery portion of the bottom of the furnace or pit.

By way of example, a preferred embodiment of the improved furnace or pitmaintenance safety cage is illustrated in the accompanying drawings, inwhich:

Fig. 1 is a perspective view of a maintenance safety cage constructed inaccordance with the invention, parts being broken away for the purposeof illustration;

Fig. 2 is a vertical sectional view through the cage located within anopen-top furnace or pit; and,

Patented Oct. .13, 1959 ventional t'op openin g furnace or pit isindicated generally at '10 comprising the side walls IL bottom 12, opentop 13, burner ports 14 and burners 15, all of which may be of anyconventional or well known design.

f The improved maintenance safety cage forming the subject matter of theinvention comprises the metallic shell 16, which may be rectangular asshown, or may be cylindrical for use within cylindrical furnaces orpits. This shell is connected at its lower end to a metal frame 17having feet or legs 18 depending from the corner portions thereof inorder to support the cage spaced above the bottom of a furnace orsoaking pit in which it is placed.

At the bottom corners of opposite walls of the cage,

the' metal shell .16 is cut away so as to form permanent openings '19.This is for the purpose of creating a downdraft through the cage to addto the workmans comfort when the cage is located within a furnaceor pitat shown in Fig. 2.

A down-draft of air is indicated by the arrows in this figure ofthedrawings, the cool air passing downward through the cage from the topthereof and through the openings 19 and then upward between the walls ofthe cage and the inner wall of the furnace or pit.

The inner side walls of the shell are lined with refractory or othersuitable thermal-insulation as indicated at 20. The bottom of the cageis formed of a plurality of horizontally slidable sections 21 slidablein grooves 22 formed in the bottom frame 17.

'An approach platform 2-3 is attached to the upper open end of the cageat one side thereof and provided with hand rails 24 in order to providesafe entrance and exit for the workman. On the inner side wall of thecage, adjacent to the approach platform 23, a ladder 25 is attached, bymeans of which workmen may descend to the bottom of the cage or toeither of the internal platforms 26 located at different heights withinthe interior of the cage.

A crane-handling bail is provided at the top of the maintenance'cage andmay comprise a pair of transversely disposed channel members 27, weldedor otherwise connected at opposite ends to the bracket plates 28 whichare welded to the side walls of the cage, a perforate plate 29 beingwelded between the channel members 27 at a point intermediate the endsthereof and provided with an elongated opening 30 to receive theconventional hook suspended from an electric crane or the like.

For the purpose of providing access to diiferent areas of the innerwalls of the furnace or pit at various heights, a plurality of doors areprovided upon each side wall of the cage, as indicated generally at 31.These doors are inwardly-opening doors and are preferably made in theform of Dutch doors, so that only one section thereof need be opened atone time in order to expose the workmen within the cage to the minimumamount of heat from the furnace or pit.

For this purpose, each door 31 comprises an upper section 32 and a lowersection 33, each section comprising a sheet metal panel 34 havinginturned marginal flanges "35 and being lined upon its interior withsuitable refractory or other thermal-insulation material as indicated at36.

Each section of each door'is hinged at one edge, as at 37, so as toswing inwardly, and is provided at its swinging edge with a latch 38operable from within the cage asby the latch handle 39, the latch 38being adapted to normally engage a keeper 40 on the exterior of the cagewhen the door section is in closed position.

Separator lintels are located between the upper and lower section orpanel or each door and each'comprises a bar or plate 41 welded atopposite ends to the outer side of the metal shell 16 of the cage andhaving an inturned flat flange 42 extending inwardly into the cagebetween the opposed edges of the upper and lower door panels orsections. These separator lintels provide means for bracing heavy handtools and the like used by the workmen in repairing the damaged furnaceor pit.

In using the above-described furnace or pit maintenance safety cage, thenecessary tools and materials for making repairs to the furnace or pitmay be placed within the cage. The cage is then picked up by a crane, bymeans of the crane-handling bail on the cage, and is lowered into thefurnace or pit to be repaired, as soon as the charge has been removedfrom the furnace and the fuel shut off.

It will be seen that when the cage is lowerd into the furnace or pit,the corner feet or legs 18 will support the cage spaced above the bottom12 of the furnace or pit. The workmen may then enter the cage by meansof the approach platform 23 and ladder 25 and may stand upon either ofthe interior platforms 26 and open any desired panel or section of anyof the adjacent Dutch doors accessible from such platform, in order towork upon the exposed area of the furnace or pit side wall, coping,burner ports or burners.

In order to make repairs upon the bottom or floor 12 of the furnace orpit, the slidable floor panels 21 of the' cage may be slidably moved togive access to any desired area of the floor of the furnace or pit uponwhich repairs are required.

It will be seen that during the time that the maintenance cage islocated within the hot furnace or pit, a down-draft will be inducedthrough the cage by means of the bottom corner openings 19 therein, coolair passing down inside of the cage and out through the openings 19 andthen upwardly between the outside of the cage and the inner walls of thefurnace or pit, as shown by the arrows in Fig. 2. Thus complete safetyand thermal comfort are provided for the workmen within the cage.

Upon completion of the work at any point on the side walls or floor ofthe furnace, the workmen will then close the door or sliding floorsection of the cage through which they have been working, and open anyother door section or sliding floor section as required to continue therepairs upon the furnace or pit.

From theabove it will be seen that the improved furnace'or pitmaintenance safety cage overcomes the disadvantages and difliculties ofusual practice in repairing the ravages to the interior of top-openingfurnaces and pits, permitting these repairs to be made immediately afterthe' charge has been removed from the furnace or pit and the fuel turnedoff, without the necessity of a lengthy cooling-off period and withcomplete comfort and safety for the workmen. Thus a furnace or pit maybe returned to use and put back into production in a very short timeafter the charge has been removed therefrom.

It will also be seen in the case of two furnaces with a common dividingwall, that it is not necessary to take both of the furnaces or pits outof production in order to'accomplish the maintenance of one, as withthis maintenance cage only the furnace or pit requiring servicing needbe shut down, since the walls of the cage provide the necessaryprotection to the workmen form the heat of the furnace. This cage isapplicable to all types of top-charge furnaces or pit-type furnaces suchas electric furnaces, soaking pits and the like.

In the foregoing description, certain terms have been used for brevity,clearness and understanding, but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchwords are used for descriptive purposes herein and are intended to bebroadly construed.

Moreover, the embodiments of the improved construction illustrated anddescribed herein are by way of example, and the scope of the presentinvention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, theoperation, and use of preferred embodiments thereof, and theadvantageous new and useful results obtained thereby; the new and usefulconstruction, and reasonable mechanical equivalents thereof obvious tothose skilled in the art, are set forth in the appended claims.

I claim:

1. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls and a bottom wall, said cage comprising an open top steel shell ofa size and shape adapted to be inserted into the furnace or pit, saidshell having side walls and a bottom heat insulating lining within saidshell, doors in all of the side walls of the cage through which a humanoperator within the cage may have access to the side walls of thefurnace or pit, and depending feet at the corners of the cage forspacing the bottom of the cage above the bottom of the furnace or pit,there being openings in the lower corner portions of the cage to inducea downdraft through the cage.

2. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls and a bottom wall, said cage comprising an open top steel shell ofa size and shape adapted to be inserted into the furnace or pit, saidshell having side walls and a bottom, a heat insulating lining withinsaid shell, doors in all of the side walls of the cage through which ahuman operator within the cage may have access to the side walls of thefurnace or pit, and slidable insulated floor sections in the bottom ofthe cage providing access to the bottom wall of the furnace or pit,there being openings in the lower portions of the side walls of the cagefor inducing a downdraft through the cage.

3. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls and a bottom wall, said cage comprising an open top steel shell ofa size and shape adapted to be inserted into the furnace or pit, saidshell having side walls and a bottom a heat insulating lining withinsaid shell, staggered doors at various heights in all of the side wallsof the cage through which a human operator within the cage may haveaccess to the side walls of the furnace or pit, and slidable insulatedfloor sections in the bottom of the cage providing access to the bottomwall of the furnace or pit, there being openings in the lower cornerportions of the side walls of the cage for inducing a downdraft throughthe cage.

4. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls with burner ports and burners therein and a bottom wall, said cagecomprising an open top steel shell of a size and shape adapted to beinserted into the furnace or pit, said shell having side Walls and abottom a heat insulating lining within said shell, doors located atdifierent heights and in staggered relation in all of the side walls ofthe cage, said doors providing access for an operator within the cage tothe side Walls of the furnace or pit and to the burner ports and burnersat various locations within the furnace or pit, slidable insulated floorsections in the bottom of the cage providing access to the entire bottomwall of the furnace or pit, depending feet upon the cage for spacing thebottom of the cage above the bottom of the furnace or pit, there beingopenings in the lower corner portions of the cage for inducing adowndraft through the cage, a platform within the cage at a point spacedbelow the top of the cage to permit a human operator standing upon saidplatform to have access to the side walls of the furnace or pit throughcertain of said doors, and a crane handling bail at the top of the cage.

5. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls with burner ports-and burners therein and a bottom wall, said cagecomprising an open top steel shell of a size and shape adapted to beinserted into the furnace or pit, said shell having side walls and abottom a heat insulating lining within said shell, doors located atdiflerent heights and in staggered relation in all of the side walls ofthe cage, each door comprising upper and lower sections, separatorlintels in the cage between the upper and lower door sections, saiddoors providing access for an operator within the cage to the side wallsof the furnace or pit and to the burner ports and burners at variouslocations within the furnace or pit, slidable insulated floor sectionsin the bottom of the cage providing access to the entire bottom wall ofthe furnace or pit, depending feet upon the cage for spacing the bottomof the cage above the bottom of the furnace or pit, there being openingsin the lower corner portions of the cage for inducing a downdraftthrough the cage, a platform within the cage at a point spaced below thetop of the cage to permit a human operator standing upon said platformto have access to the side walls of the furnace or pit through certainof said doors, and a crane handling bail at the top of the cage.

6. A top opening furnace or pit maintenance safety cage for protectinghuman operators from the heat of an open top furnace or pit having sidewalls with burner ports and burners therein and a bottom wall, said cagecomprising an open top steel shell of a size and shape adapted to beinserted into the furnace or pit, said shell having side walls and abottom a heat insulating lining within said shell, doors located atdifferent heights and in staggered relation in all of the side walls ofthe cage, each door comprising upper and lower sections, separatorlintels in the cage between the upper and lower door sections, saiddoors providing access for an operator within the cage to the side wallsof the furnace or pit and to the burner ports and burners at variouslocations within the furnace or pit, slidable insulated floor sectionsin the bottom of the cage providing access to the entire bottom wall ofthe furnace or pit, depending feet upon the cage for spacing the bottomof the cage above the bottom of the furnace or pit, there being openingsin the lower corner portions of the cage for inducing a downdraftthrough the cage, a platform within the cage at a point spaced below thetop of the cage to permit a human operator standing upon said platformto have access to the side walls of the furnace or pit through certainof said doors, a crane handling bail at the top of the cage, a ladderwithin the cage on one side wall thereof, and an approach platformextending outwardly from the top of the cage adjacent the top of saidladder.

References Cited in the file of this patent UNITED STATES PATENTS298,203 Hickman May 6, 1884 1,578,474 Shawl Mar. 30, 1926 2,019,162Sipchen Oct. 29, 1935

